Loom dobby



NOIV- 1967 E. PFARRWALLER 3,352,328

' LOOM DOBBY Filed March 19, 1965 5 Sheets$heet l Inventor:

ER WIN PFARRWALLER 5y MM W ATTOR/VE Y I N v- 1 1967 E. PFARRWALLER LOOM DOBBY 5 Sheets-Sheet Filed March 19, 1965 Inventor: By ERW/N PFARRWALLER ArroRA/Em Nov. 14, 1967 E. PFARRWALLER 3,352,328

LOOM DOBBY Filed March 19, 1965 5 Sheets-Sheet 4 Inventor: BY ER W/N PFARR WALLER ATTORNEY5 Nov. 14, 1967 E. PFARWALLER 3352,5328

LOOM DOBBY Filed March 19, 1965 5 Sheets-Sheet 5 Inventor:

ER WIN PFA RR WALLER ATTORNE Y5 United States Patent 3,352,328 LOOM DOBBY Erwin Pfarrwaller, Winterthur, Switzerland, assignor to Gebruder Sulzer Aktiengesellschaft, Winterthur, Switzerland Filed Mar. 19, 1965, Ser. No. 441,203 Claims priority, application Switzerland, Apr. 3, 1964, 4,281/ 64 8 Claims. (Cl. 139-68) This invention relates to looms and is particularly concerned With the control of a loom dobby comprising reciprocating lifting beams and lifters engageable with the beams, and which lifters are drivingly connected with the heddle frames of the loom. The dobby structure also comprises an actuator which controls the dobby for engagement of the lifters with the lifting beams according to a pre-set weaving program, and said structure also comprises a separate linkage for each pair of lifters associated with a heddle frame.

Dobbies of the nature referred to generally are known, and in one type the actuator drive, which takes the form of two reciprocating leaves or arms or the like, guides the actuator linkages to beyond the central position of the motion thereof, whereupon the drive ceases to operate. A spring, particularly a snap-action spring device, is stressed during the first portion of the actuating movement and, after the linkage moves beyond the central position, will utilize the stored power of the spring to move the linkage to the end position thereof opposite its starting position. In this known type of actuator drive, hydraulic piston means are employed for braking the linkages as they approach the last-mentioned end position, and upon the linkages reaching the said end position, they will be retained therein by their respective springs. This arrangement has the disadvantage of requiring the over-center or snap-action spring mechanisms associated with the linkages, and furthermore, require the hydraulic braking or cushioning devices referred to.

According to the present invention, a simpler, more reliable, more inexpensive structure is employed in connection with a dobby of the nature referred to by associating a friction brake with each linkage in a particular manner. A friction brake forms a simple reliable device for retaining the linkages, and therefore the lifters, in their end position. The lifters will remain engaged with or disengaged from the lifting beams depending on the operation of the lifters when last actuated. The snap-action spring device can be eliminated and the hydraulic piston means for cushioning or braking can also be eliminated.

The friction brake arrangement is substantially uniform because there is no appreciable change in the coetficient of friction in response to temperature changes which does materially affect a damping liquid such as is employed with hydraulic pistons. Since the braking action is uniform and reliable, the friction brake according to the present invention can be so devised that the moving parts of the linkage have reduced mass which, of course, assists in the actuation thereof and also reduces the mass which must be braked on each actuation of the linkages.

In one embodiment of the invention, a brake plate is provided between relatively large area portions of two adjacent linkages of the actuator. This arrangement is compact and, in many cases, does not represent any increase in size of any of the parts of the dobby because relatively large area levers or arms are employed in the dobby structure in any case.

In one arrangement according to the present invention, means are provided for automatically adjusting the force of a spring associated with the brakes in response to movement of the actuator. Such a system can be devised,

3,352,328 Patented Nov. 14, 1967 for example, to increase braking force near the end of the actuator movement so that the parts are braked to a lesser extent while in motion to provide for easier actuation thereof but are more strongly braked while stationary. More particularly, a control system of this nature can be devised to provide a substantially constant but reduced braking during the first half of actuator movement and a substantially constant but increased braking during the second half of the actuator movement. This last-mentioned brake device thus meets the requirement that the parts must be accelerated during the first half of the movement and decelerated during the second [half of their movement. It will be apparent that this can be best accomplished by friction braking as opposed to a snap-action spring device which has been heretofore employed.

In one form of the invention, a rod on which the braking members are mounted has a passage therein for supplying liquid to the moving parts for lubrication and also for damping those parts which move into engagement at the end of an actuating movement. In one embodiment of the invention, the aperture from which the liquid issues is a slot having a cross section only slightly greater than the diameter of the rod so that the area through which the liquid passes is bounded. The damping liquid in this case acts as an extra brake throughout the movement of the parts.

From the foregoing it will be appreciated that a primary object of the present invention is the provision of an improved loom dobby having improved actuating means and, in particular, improved control means for controlling the operation of the lifters during actuation thereof.

The exact nature of this invention will become more apparent upon reference to the following specification taken in connection with the accompanying drawings, in

which:

FIGURE 1 is a sectional view showing the actuating mechanism of the dobby according to the present invention;

FIGURE 2 is a section taken along line IIII of FIGURE 1;

FIGURE 3 is a graph showing the motion of the parts of the structure of FIGURE 1;

FIGURE 4 is a view like FIGURE 1 which shows a modification;

FIGURE 5 is a section on line VV of FIGURE 4;

FIGURES 6' and '7 are fragmentary sectional views similar to FIGURES l and 4 but showing respectively different modifications;

FIGURE 8 is a sectional view indicated by line VIIIVIII on FIGURE 9 showing a part of the control system;

FIGURE 9 is a section on line IXIX of FIGURE 8;

FIGURE 10 is a schematic view showing a cam and roller combination such as would be employed with the FIGURE 9 structure for varying the force of the brake spring, and

FIGURE 11 is a view like FIGURE 10 but shows a different cam structure to vary the brake spring force.

Referring to the drawings somewhat more in detail, FIGURE 1 shows a casing 1 which is attached to a loom structure which is not illustrated in the drawings. Mounted within casing 1 is a dobby structure adapted for being controlled by a perforated record according to practices already known in the loom art, such card controls being illustrated for example in Patents 3,101,745 and 3,101,- 746.

The card dobby comprises a shaft 2 to which a first actuating leaf 3 is fastened. Disposed on the shaft 2 with the inter-position of a needle bearing 10 is a hollow shaft 4 to which a second actuating leaf 5 is fastened. The

two shafts 2 and 4 are so driven intermittently and in respectively opposite directions that the two leaves 3, 5 first move from the common central position (dotted line in FIGURE 1) into outer positions (leaf 3 in dot-dash line position, leaf 5 in dashed line position), then return to the dotted-line central position, then move so that each leaf occupies the outer positionpreviously occupied by the other leaf (leaf 3 in the dashed line position, leaf 5 in the dot-dash line position), and finally to return to the dottedline central position. The top leaf 3 therefore moves as indicated by curve D in FIGURE 3 and the bottom leaf 5 movesas indicated by curve E in FIGURE 3. The curves are plotted along an abscissa marked in degrees of loom main shaft rotation. Points G on the curves D, E denote the dashed-line left-hand position in FIGURE 1, points S denote the dot-dash line right-hand position in FIG- URE l, and points P denote the dotted-line central position in FIGURE 1.

A perforated card 7 containing the weave program for the fabric runs over a vertically movable control roller 6 (FIGURE 1). Feelers 8, only one of which can be seen in FIGURE 1, are disposed above the roller 6 and rest on the perforated card. Each needle 8 is vertically movable in a guide and has a head to prevent it from slipping through the guide. An actuating rod 11 bears at its end 9 against the needle 8 and is articulated to an actauting member or lever 13 via a pivot 12. A rod 11, needle 8 and lever 13 are provided for each heddle frame of the loom, i.e., if there are, for instance, 20 heddle frames there are 20 parts 11, 8, 13.

When a perforation in the card 7 is below the needle 8, the rod 11 drops into the bottom position shown in FIGURE 1, the needle 8 engaging in the roller 6 and the rod 11 being in the lower position in which it cooperates with the leaf 5. In the absence of perforation below the feeler or needle or the like 8, the same rests on the card 7 and therefore, substantially, on the periphery of the roller 6. The rod 11 is then in its raised position in which it is in engagement with the leaf 3. This obtains for all the feelers 8.

The rods 11 can therefore be selectively reciprocated under the control just of the two leaves 3, 5 in accordance with the program punched on the card 7.

The levers 13 are mounted for rotation on a spindle 14 disposed in the casing 1. All the levers 13 are identical and have three arms 15, 16, 17. The arm 17 has a tooth 18 which engages in a lever 21 pivotable around a spindle 19. The unit formed by five associated parts 11,13, 21, 24, 25 forms one linkage. Bent links 24, 25 are articulated to the lever 21 via pivots 22, 23 and each has its other end articulated via a pivot 26, 27 to one hooked end 28, 29 of one of lifters 31, 32. Each pair of lifters 31, 32 is articulated via pivots 33, 34 to a cam 36 pivotable around a spindle 35. Rollers 37, 38 mounted on a lever 41 pivotable around the spindle 39 run on the cam 36, and the lever 41 acts on other elements (not shown) to control the associated heddle frames i.e., to bring the same into the top shed or bottom shed or center shed position or the like.

Curves A, B in FIGURE 3 represent the motion of.

two heddle frames or two groups thereof. As can be gathered, the heddle frames are in the top shed or bottom shed position whenever the main drive shaft isat its 180 position, shed-changing occurring at 0 and 360.

Two lifting beams'42, 43 of the dobby are reciprocatcd vertically, as indicated by arcs 44, 45 in FIGURE 1, and by curve C in FIGURE 3, during operation. Ends 28, 29 of the lifters can be selectively engaged with one of the lifting beams 42, 43 by the pivoting reciprocation of the levers 13, 21. Any one lifter can be engaged with the beams when the same are in the top and bottom positions. In FIGURE 1 the lifter 32 has just engaged with the beam 43. The cam 36 therefore reciprocates continuously during the movement of the lifting beams so that the associated heddle frame is reciprocated vertically.

The lifter 31 is also driven by the cam 36 and moves continuously past the beam 42, but in the opposite direction of movement. If, for instance, the rod 11 is operated to disengage the lifter 32 before the, next pick (movement of the elements 18, 21, 24, 25 to the left in FIG- URE 1) the beams cease to be connected to the lifters. The cam 36 and the associated heddle frame stay inthe position in which they were. When the lifting beams 42, 43 descend, the beam 42 strikes the end 28 of the lifter 31 to pivot the elements 18, 21, 24, 25, 31, 32 into the position shown in FIGURE 1. During the next ascent of the lifting beams, the beam 43 strikes the end 29 of the lifter 32 so that the elements 18, 21, 24, 25, 31, 32 move to the left, the cam 36 and the associated heddle frame remaining stationary. This condition continues until the weave program on the card 7 acts via the actuating system-3, 5,11, 13 to engage. one of the lifters with its lifting beam, whereafterthe cam 36 and associated heddle frame start to move again.

The free and large surface arm 16 of each lever .13 is formed with a slot 46 and a rod 47 extends through all the slots 46. The rod 47 also extends through brake plates 48 made of a substance having an appropriate coefficient of friction, such as the brass-like copper-zinc-manganese alloy commercially known as AETERNA. The free arm 16 of a lever 13 extends between every two brake plates 48. The same are suspended from a square beam 49 secured to the casing 1 and formed with a longitudinal passage .51 serving to distribute a damping liquid, such as oil, which is removed through a passage 52 and a number of passages 53. As each lever 13 pivots, the beam 49 forms abutments 54, 55 which are wetted by the damping liquid. This feature insures that there is no impact of metal on metal at the end of the actuating movement of the actuator.

Allthe plates 48 and the arms therebetween form a group biased by a spring 56 whose force is adjustable by nuts 57. The brake plates insure that the motion of the levers 13 and the elements 11, 21, 24, 25, 31, 32 drivingly connected thereto is always braked at the same strength. When the latter elements are stationary-i.e., after the lifters have been engaged with or disengaged from the lifting beams, or whenever any of the lifting beams 42, 43 have just knocked back a lifter, the plates 48 retain the elements in the position in which they have stopped.

In the embodiment shown in FIGURES 4 and 5, a rod 49a is used as a support for circular brake plates (brake discs) 48a. The rod 49a. is disposed in an are 58 of each lever 13, such as are. being formed between the two free arms 15, 16.

The embodiments shown in FIGURE 6 use levers 13a Whose projecting arm 16a is formed with an aperture 58a, and a rod 49a extends through all the apertures 58a and form the two abutments 54, 55 as the lever 13a reciprocates. Oil is supplied to the passage 51 through a channelin the end face of therod 49a and departs through passages 53 to a chamber 70 whence it departs through passages 59 to lubricate other parts of the dobby.

The embodiment shown in FIGURE 7 uses a slot-like aperture 58b whose cross-section is very little larger than the cross-section of the rod 49a. The same therefore cooperates with the slot 58b to bound constrictions 71 as shown oversize in the drawing for the. sake of clarity. Upon actuation oil is displaced, for instance, from space 70a through the constriction 71 into space 70b, so that there is a hydraulic damping, as well as the action of the friction brake plates 40a in respect of the whole movement of the lever.13a. There is no direct or discharge channel from the space 70a, 70b; instead, a pump is connected to the channel 51 just to maintain an oil pressure and compensate for leakage losses.

In the embodiment shown in FIGURES 8-10, one actuating leaf, namely, the leaf 3, mounted on a square end 2a of the shaft or spindle 2, is articulated via a link 64 to one arm 62 of a double-armed lever 62, 63 freely rotatable around a spindle 61. The arm 63 has a cam 65 which cooperates with a roller 66 disposed on a free end 67 of a rod 471); the same extends through the brake plates 48 and has its other end loaded by a spring 56. The tendency is for the group formed by the elements 16, 48 to be forced to the left in FIGURE 9 against an abutment 60 so that the roller 66 is kept in engagement with the cam 65. The cam 65 has at both its ends raised parts 65a which act when the leaf 3 is deflected into one or the other end position.

When the leaf 3 returns to the dotted-line central position in FIGURE 1, a recessed part 65b of the cam lies under the roller 66. The braking provided by the plates 48 is therefore so controlled that braking is increased during actuationi.e., during the deflection of the leaves 3, 5for the roller 66 and rod 47b are forced to the left in FIGURE 9 during the actuating time, so that the stressing of the spring 56 increases. Upon completion of actuation, after all the parts have been braked and have stopped, the leaves return to the dotted-line central position in FIGURE 1, such position being opposite the recessed part 6511. The stressing of the spring 56 is therefore decreased but is adequate to retain the parts in the end position.

Referring now to FIGURE 11, a cam 650 has on both sides of its center 73 portions 74 upon which the roller 66 does not rise. In these regions, therefore, braking is at a minimum just as at the center 73. The length of each portion 74 corresponds to half the actuating movement of the leaves 3, 5, i.e. to that portion of the actuating movement during which the parts must be accelerated. Braking is therefore reduced during this portion of the actuating movement. The cam 65 then rises on both sides on to the sections 75, the same being of a length corresponding to the second half of the actuating travel, i.e., the half during which the parts must be decelerated. This requirement is met by the increased constant braking which is maintained to the end of the actuating movement.

As an alternative, the friction brake system can be disposed on some other part of the linkage 11, 13, 21, 24, moved by the leaves 3, 5; for instance, brake plates can be disposed between all the levers 21 and can be mounted, for instance, on the spindle 19. A friction brake system could also be devised which does not comprise a number of plates introduced between every two adjacent large area parts of the linkage 11, 13, 21, 24, 25 but which acts, for instance, from above and below, on the rods 11 and brakes the same in their horizontal reciprocation. Control of the brake can be derived from some element other than the leaves 3, 5 for instance, from a special cam of the dobby.

In all the examples given the main braking occurs during the engagement or disengagement of the liftersi.e., when the lifting beams 42, 43 force back the parts 11, 13, 21, 24, 25, 31, 32. The action of the damping liquid is an extra and is limited, for instance, to insuring that those elements 15, 16, 49 (or 49a) which strike one another at the end of the actuating movement experience a reduced impact because of the oil film between them.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and, conditions; and accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

What is claimed is:

1. A loom dobby comprising two reciprocating lifting beams, a plurality of pairs of heddle frame lifters, a separate movable linkage coupled to each of said pairs of lifters, each said linkage including a member shiftable between two end positions in each of which a separate lifter of the pair coupled to that linkage is engageable with a separate one of said beams, said shiftable members being arranged in spaced aligned arrangement, a separate brake plate disposed between each two adjacent ones of said aligned members, a rod on which said brake plates are engaged, and resilient means to stress said aligned members and brake plates together.

2. A dobby according to claim 1 wherein said members have a bifurcated extension about said rod with clearance therefrom, said clearance being dimensioned to bring each of said members into abutment with said rod at each of the end positions for such member.

3. A dobby according to claim 2 in which said rod includes a passage for damping fluid extending lengthwise of said rod and bores between said passage and the surface of said rod disposed between adjacent of said brake plates.

4. A dobby according to claim 1 wherein said members contain each an aperture about said rod, said apertures having a dimension parallel to the direction of motion of said members between their end positions suflicient to permit motion of said members between their said end positions and a dimension perpendicularly of said direction of motion providing close clearance from said rod, said rod including a passage for damping fluid extending lengthwise of said rod and bores between said passage and the surface of said rod disposed between adjacent of said brake plates, said bores extending substantially perpendicularly of said direction of motion.

5. A dobby according to claim 2 wherein said members are pivotally supported on a common shaft parallel to said rod.

6. A dobby according to claim 1 including oscillating means to drive said linkages and thereby to shift said members between their end positions, and stress varying means coupled to said oscillating mean to vary, with motion of said oscillating means, the engagement of said brake plates with said shiftable members.

7. A dobby according to claim 6 wherein said stress varying means cause the frictional load imposed by said brake plates on said shiftable members to vary directly with motion of said shiftable members from an intermediate position toward either of their said end positions.

8. A dobby according to claim 6 wherein said stress varying means comprise a cam coupled to said oscillating means, a follower coupled to said cam, and resilient means coupled to said follower for stressing said brake plates against said members, said cam having high points en gaged under said follower means for positions of said oscillating means in which said members are disposed in either of their end positions, to impose a greater frictional load on said members in said end positions thereof than in intermediate positions thereof.

References Cited UNITED STATES PATENTS 2,085,459 6/1937 Wiget 139-68 2,644,488 7/ 1953 Pfarrwaller 139-68 2,655,231 10/1953 Rossire 18883 3,101,746 8/1963 Pfarrwaller 13968 3,103,357 9/1963 Berne 18872 X 3,156,321 11/1964 Deyerling et al. 18872 X MERVIN STEIN, Primary Examiner.

H. JAUDON, Assistant Examiner. 

1. A LOOM DOBBY COMPRISING TWO RECIPROCATING LIFTING BEAMS, A PLURALITY OF PAIRS OF HEDDLE FRAME LIFTERS, A SEPARATE MOVABLE LINKAGE COUPLED TO EACH OF SAID PAIRS OF LIFTERS, EACH SAID LINKAGE INCLUDING A MEMBER SHIFTABLE BETWEEN TWO END POSITIONS IN EACH OF WHICH A SEPARATE LIFTER OF THE PAIR COUPLED TO THAT LINKAGE IS ENGAGEABLE WITH A SEPARATE ONE OF SAID BEAMS, SAID SHIFTABLE MEMBERS BEING ARRANGED IN SPACED ALIGNED ARRANGEMENT, A SEPARATE BRAKE PLATE DISPOSED BETWEEN EACH TWO ADJACENT ONES OF SAID ALIGNED MEMBERS, A ROD ON WHICH SAID BRAKE PLATES ARE ENGAGED, AND RESILIENT MEANS TO STRESS SAID ALIGNED MEMBES AND BRAKE PLATES TOGETHER. 